Banca de DEFESA: CARLOS ALBERTO RIBEIRO DE MOURA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : CARLOS ALBERTO RIBEIRO DE MOURA
DATE: 25/09/2020
TIME: 09:00
LOCAL: videoconferencia
TITLE:

Influence of edaphic ant fauna on physical, chemical and microbiological properties of soils in a land use gradient

KEY WORDS:
PAGES: 130
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SUMMARY:

MOURA, Carlos Alberto Ribeiro de. Influence of edaphic ant fauna on physical, chemical and microbiological properties of soils in a land use gradient. 2019. 000 p. Thesis (Doctor Science in Agronomy, Soil Science). Instituto de Agronomia, Departamento de Solos, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, 2019.

This study addressed the effects of the Solenopsis invicta Buren (SI) on bioturbation and nutrient stocks in soils under agroecological management, the occurrence of biological nitrogen fixation in SI and the attraction of ant assemblyto attractive plant crops. Edaphic ants are an important group of bioturbators, and SI are widely found in agroecosystems. SI can be classified as generalist predators and are efficient at exploring disturbed environments. In Chapter I, the hypothesis that SI when building their nests and acting as biological vectors of nutrients alters nutrient levels and soil fertility parameters as C, N, P, K, Ca, Mg, Si, H + Al, V%, the granulometric fractions and the phytoliths assembly (Poaceae, Eudicotyledonae, Arecaceae, Cyperaceae) was verified. In Chapter II, the hypothesis that this SI in association with nitrogen-fixing bacteria would be able to perform biological nitrogen fixation was assessed. And in Chapter III, the ability to use attractive plants (PAs) to attract the myrmecofauna was tested. There was an increase in the concentration of C, P, K, in V% and coarse sand and a reduction in total acidity and in total clay in the nests. The phytolith assembly changed in three of the four groups analyzed and the silicon content PASi (Si available for plants), ASi (amorphous silica) and AIF (acid insoluble fraction) showed a strong increase in relation to the control soil, with ASi presenting mean difference of 243.23 g.kg of soil. All samples submitted to acetylene reduction analysis showed ethylene production and the average fixation was 4.3 nmol of fixed N. g (wet weight).h^-1 (n = 44). The bacteria associated with SI were identified through metagenomics. The genera that comprise species with known FBN capacity make up an average of 26.24% of the genera present in the samples and the regression model was significant for the genera Bradyrhizobium (p = 0.0025; R² = 0.5464) and Sphingomonas (p = 0.00434; R² = 0.506). The activity data obtained in the PAS experiment submitted to multivariate analysis of PERMANOVA did not detect any difference between treatments but detected between sampling events which translates as an effect of the time that has elapsed since the last plowing. These silicon data can have an impact on soil carbon studies, especially its inorganic component, on the understanding of silicon dynamics and serve as a basis for studies with solubilizing bacteria by pointing out nests as possible centers of activity for these bacteria. It is assumed that FBN in SI is an important holophenotype for the success of SI as an invading holobiont and skilled in exploring disturbed areas. This is the first study indicating the occurrence of FBN in ant workers and reveals a source not yet quantified in agroecosystems and natural ecosystems. As there was no effect of the treatments, it is recommended that a vegetation cover is maintained, even if spontaneous, and that these refuges are not submitted to plowing, thus maintaining the diversity of the myrmecofaunaand the services that itcan provide.

BANKING MEMBERS:
Externo à Instituição - FABRICIO BEGGIATO BACCARO - UFAM
Interno - 084.646.497-70 - EDERSON DA CONCEIÇÃO JESUS - EMBRAPA
Externo ao Programa - 1767348 - FABIO SOUTO DE ALMEIDA
Interna - 387335 - LUCIA HELENA CUNHA DOS ANJOS
Presidente - 932.320.637-72 - MARIA ELIZABETH FERNANDES CORREIA - UFRRJ
Externa à Instituição - MARIELLA CAMARDELLI UZÊDA - EMBRAPA